One of two in Monopoly (3)
I believe the answer is:
die
'one of two in monopoly' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for die that I've seen before include "Device that stamps design on metal" , "One of a pair of dice" , "Mould; become extinct" , "Cease living" , "Cease to exist" .)